Acoustic horn



July 15 1924.

'M. ABRAHAMS ACOUSTIC HORN Filed Feb. 28, 1924 ATTORNEYS Patented July 15, 1924.

UNITED STATES max ABRAHAMS, or NEW YORK, N. Y.

ACOUSTIC BORN.

Application filed February 28, 1924. Serial No. 695,687.

T all whom it may concern.

Be it known that I, MAX ABRAHAMS, a citizen of the United States, residing at New York city, in the county of New York and State of New York, have invented certain new and useful Improvements in Acoustic Horns, of which the following is a full, clear, and exact description.

This invention relates to acoustic horns and particularly to the type utilizing a fabric for the reinforcement. Various attem ts have been made to produce such. horns iy impregnatin a fabric with suitable fillers, paints, varnlshes and the like, but the orus dinary fabric which has been used heretofore for this purpose does not take up or receive sufiicient of the filler to give the necessary rigidity, strength, and thickness to the walls of the horn. The walls of such prior devices were thin and weak andwere, therefore, likely to vibrate and impart to the sounds being amplified within the horn an undesirable effect. The materials used in the prior devices have also been comparatively expensive.

An ob ect of this invention is to provide an improved acoustic horn of this eneral type, which will give superior acoustical results; whose walls will have a minimum tendency to vibrate and thus undesirably modithe sound being amplified; which will be light in weight, strong, rigid, and self supporting; and which will be simple and relatively inexpensive. A further object is to provide an improved method of making such an acoustic hoin, which will provide a satisfactory article with a minimum of steps and ap aratus. Other objects and advanta es wi 1 be apparent from the following description of an embodiment of the invention, and

the novel 'features will be particularly pointed out hereinafter in claims.

In the accom anying drawing: Fig. 1 is an e evation partly in section of 4 a horn constructed in accordance with the invention; and

Fig. 2 is a section of a portion of a wall thereof, on a larger scale. 7

In this illustrated embodiment of the invention a heavy textile fabric 1 is cut and stitched .into the desired shape and size of the horn, or is otherwise fashioned into the desired shape, form and size, and is then stretched upon a suitable form (not shown) which holds the fabric expanded and in proper shape. The textile fabric is preferably a heavy fabric having a pile or nap, such as the type of'fabric commonly known as fleece-lined and used in underwear, but it will be understood that various other fabrics may be employed. The stretched fabric is then impregnated with a suitable filler,

paste, or glue 2 (see Fig. 2) such as a dextrine paste. Such a paste may be formed by a mixture of glue and dextrine or dextrine alone may be used.

After the fabric is thoroughly impre nated, the form with the impregnated fa ric .thereon is baked, to thoroughly harden the filler or impregnating material. The impregnating material will be taken up in considerable quantities by the nap or pile, and to a greater extent than would be the case if plain fabric were utilized. The resulting product, therefore, will have greater thickness, rigidity, and strength, with a minimum weight of fabric. The hardened impregnated fabric is then removed from the form, and if desired, a coating of the paste or filler may be applied to both the inner and outer faces in order to fill in the intersticesand provide a smoother surface, which slightly increases the thickness and strength ofthe walls. After this coating has hardened, or has been baked until it has become hard, the horn is given a surface coating 3 of a suitable cheap paint, such as a water paint formed of glue, oil and water, after which the horn is allowed to dry and harden in air or is baked to harden the paint. A suitable coloring or finishing decorative coating may then be applied.

I have found that with a horn constructed in this manner, the acoustical results are very materially improved over the prior horns which utilize a plain fabric, and such horns are more rigid and durable and the walls have a lesser tendency to vibrate. The cost of. manufacture is very low and very little apparatus is necessary for the manufacture of such horns.

It will be obvious that various changes in the details and arrangements of arts, herein described and illustrated for t e purpose of ex laining the nature of the invention, may be made by those skilled in the art within the principle and scope of the inven tion, as expressed in the appended claims.

I claim:

1. An acoustic horn comprising a base form of textile fabric with a pile surface forin being im regnated with a hardened and having the desired shape and size, said filler of glue an dextrine, and having assurform being impregnated wlth a watersolufacefinishing coating of a water paint. 10 bis vfiller giving ri idity t0 the form. In witness whereof; I hereunto subscribe 5 2. An acoustic orn comprising a base my signature.

form of textile fabric with a pile surface and having the'desired shape and size, said MAX ABRAHAMS. 

